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Assembly Drawings, Balloons, and Parts Lists

Working Drawings A design that has been approved for prototype or full-scale manufacture requires a set of working drawings to communicate the object’s geometry to everyone involved with its manufacture and assembly. Working drawings are a complete set of documents that include: Individual part drawings One or more assembly drawings A parts list

Assembly Drawings An assembly drawing shows how all of the parts of a multi-component design fit together, and are generally depicted as one or more orthographic projections. One or more full section views are often used in an assembly drawing to show necessary internal features.

Example Assembly Drawing

Information from Assemblies Assembly drawings may contain the following: One or more views, including sections or auxiliaries Enlarged views to show small details Overall or specific dimensions needed for assembly Notes on manufacturing processes required for assembly Balloons to indicate item numbers Parts list or bill of materials (BOM)

Assembly Drawings, Balloons, and Parts Lists Introduction to Engineering Design TM Unit 2 – Lesson 2.3 – Advanced Modeling Skills Types of Assembly Drawings Design Assembly General Assembly Detail Assembly Erection Assembly Subassembly Pictorial Assembly There are several different types pf assembly drawings. The style and information included depends on the needs of the end user. As with all drawings being clear and concise with the information are the goal. Detailed drawings cover the size and shape issues on each individual parts. The assembly drawings are used to deliver any and all other information needed in the life cycle of the product. Project Lead The Way, Inc. Copyright 2007

Design Assembly Design assemblies are used to show various relationships between components. The design assembly at the right shows the kinematic relationship that exists between the fly wheel’s 360° rotation, and the extreme angular motion of the piston cylinder body.

Design Assembly Design assemblies are often made from sketches during the preliminary phases of a design process to study the relationships that exist between the components before the design is modeled.

General Assembly A general assembly is the most common type of assembly drawing. It is displayed as a multiview drawing and may contain a section view. General assemblies do not contain dimensions.

Assembly Drawings, Balloons, and Parts Lists Introduction to Engineering Design TM Unit 2 – Lesson 2.3 – Advanced Modeling Skills Detail Assembly A detail assembly is a combination of an assembly view with several of its parts depicted as dimensioned multiview drawings on one drawing sheet. This practice, though not common, reduces the number of drawing sheets needed, and is more appropriate for designs with small numbers of components. Project Lead The Way, Inc. Copyright 2007

Assembly Drawings, Balloons, and Parts Lists Introduction to Engineering Design TM Unit 2 – Lesson 2.3 – Advanced Modeling Skills Example Detail Assembly Project Lead The Way, Inc. Copyright 2007

Erection Assembly Similar to general assemblies, except dimensions and fabrication specifications are commonly included. Typically associated with cabinetry or products that are made from structural steel. Used for both fabrication and assembly.

Subassembly Drawing Flashlight Subassembly Complex or large assemblies may be communicated through subassembly drawings.

Pictorial Assembly Usually depicted as an isometric or perspective drawing. May be rendered to imitate photographic quality. Uses include: - Sales promotion - Customer self-assembly - Maintenance procedures

Pictorial Assembly Drawings Pictorial assemblies are often used in catalogs, journal articles, and advertisements. This pictorial is sectioned to show interior details.

Pictorial Assembly Drawings Exploded pictorial assembly drawings are commonly used to show how individual components fit together.

Balloons A balloon is a circle that contains a single number, which is connected to an assembly component with a leader line.

Balloon Guidelines All balloons on a drawing should be the same size. Balloons should be grouped together in an easy- to-read pattern. Balloon numbers must correspond to item numbers in a parts list. Balloons should not have horizontal or vertical leader lines.

Parts List A parts list is a table that contains information about each of the parts contained in an assembly. The item numbers correspond with the balloon numbers.

Example Parts List

Parts List Information Items commonly found in a parts list include: Item number – from balloons. Quantity – the number of a particular part needed for the assembly. Part or drawing number – a reference back to the detail drawing. Description – usually the part name or complete description of a purchase part. Material identification – the material of the part. Information about vendors – for purchase parts.

Parts List Location The location of a parts list usually depends on company standards. Common locations include: Above the title block – most common Upper right corner Upper left corner A convenient location on the drawing

Parts List Location